Process for dye levelling with lactams



United States Patent 3,096,142 PROCESS FOR DYE LEVELLING WITH LACTAMS Bjarne Hartmark, Curt Schuster, and Karl Herrle, all of Ludwigshafen (Rhine), Germany, assignors to Badische Auilin- & Soda-Fabrik Aktiengesellschaft, Ludwigshafen (Rhine), Germany No Drawing. Filed July 9, 1958, Ser. No. 747,351 Claims priority, application Germany July 10, 1957 11 Claims. (Cl. 8-85) This invention relates to new dyeing auxiliaries, especially for levelling dyeings, and to the levelling of dyeings with dyeing auxiliaries not hitherto used for this purpose.

The object of the invention is to provide dyeing axuiliaries which above all are especially active and productive as levelling agents. A further object of the invention is to carry out levelling with dyeing auxiliaries which do not disturb the dyeing process. A further object of the invention is the use of the dyeing auxiliaries for subsequent levelling (levelling out) dyeings which are not level. Other objects of the invention will become apparent from the explanations given in the following description.

The objects of the invention are achieved by compounds which contain in the molecule at least two lactam radicals which are connected through their nitrogen atoms by a carbon chain interrupted by at least one hetero atom, the number of carbon atoms between a lactarn nitrogen atom and the hetero atom being 2 to 6.

The said lactarn radicals may contain 5, 6 or 7 ring members, i.e. they may be the radicals of butyrolactam, valerolactam or caprolactam. The lactam radicals may also hear substituents on the carbon atoms, as, for example, alkyl radicals. Alkyl radicals with only a few carbon atoms, as for example the methyl, ethyl or propyl radicals, may be the substituents. The lactam radicals in the dyeing auxiliaries may be identical or different.

The hetero atoms by which the carbon chains between the lactam radicals are interrupted are nitrogen, oxygen or sulfur atoms. The third linkage of the nitrogen atom my be combined with a hydrogen atom or with an aliphatic or cycloaliphatic radical. The length of this aliphatic radical may amount to 1 to 5, preferably 1 to 4, carbon atoms. The aliphatic radical may also bear further radicals, for example a hydroxyl group which may also be etherified, a nitrilc group, an amino group or a lactam radical. The number of hetero atoms, i.e. of nitrogen, oxygen or sulfur atoms, in the carbon chain between the lactam radicals may be for example 1, 2, 3, 4, 5, 10 or 20, or even more. The hetero atoms may be identical or different.

The details given above regarding the constitution of the compounds which are useful according to this invention may be summarized by the following general formula, it being understood that this general formula is intended to serve merely for explanation of the invention of the invention and not by way of limitation of the invention:

L represents identical or different lactam radicals derived from butyrolactam (pyrrolidone) valerolactam or caprolactam, R represents a chain of from 2 to 6 carbon atoms in length, R represents a chain of from 1 to 6 carbon atoms in length,

3,096,142 Patented July 2, 1963 2 n represents 0, 1, 2, 3, 4, 5, or any further integer up to 10, 20 or more, X represents 1, 2, 3, or all of the groups --N, N, 0- or S R being an aliphatic radical of l to 5, preferably 1 to 4, carbon atoms in length, which radical may bear other substituents or a cycloaliphatic radical, for example cyclopentyl.

For the sequence of carbon atoms including the said hetero atoms between the nitrogen atoms of the lactam radicals we use in this description also the expression connecting chain." For the dyeing auxiliaries suitable according to this invention we also use the expression lactam compounds.

A few examples of R are: methyl, ethyl, propyl,

For purposes of illustration we specify some of the compounds:

n being any number from 2 to 6, identical or difierent n' may also be 1.

Lactam compounds of the said kind are obtained, for example, by reaction of symmetrical dichlordiethyl ether or symmetrical dichlordiethylthioether with a lactam, for example with pyrrolidone or caprolactam, or by reaction of tri-(chlorethyU-amine with the said lactams or by reaction of polyalkylene polyamines, as for example diethylene triamine, N-rnethyl-diethylene triamine, triethylene tetramine or the corresponding propylene derivatives, with lactones, such as butyrolactone or valerolactone. Instead of the simple lactams or lactones, there may also be used for the reaction lactams or lactones which are substituted on carbon for example by lower alkyl or cycloalkyl radicals.

By reaction of butyrolactone with diethylene triamine there is obtained for example the compound:

By reaction of butyrolactone with dipropylene triamine there is obtained for example the compound:

By reaction of butyrolactone with triethylene tetramine there is obtained for example the compound:

By reaction of butyrolactone with N-methyldipropylene triamine there is obtained the compound:

LCH1OH CHzN-CH CHi-CHzL By reaction of 2 mols of a lactam substituted on the nitrogen atom by the beta-chlorethyl group with 1 mol of sodium sulfide there is obtained for example the compound:

-CH -S-Cl-I CH -L+2NaCl By reaction of butyrolactone with di-(gamma-aminopropyl)-ether there is obtained the compound:

In these formulae L, depending on the lactones used in the manufacture, may represent for example:

It may be said quite generally that the dyeing auxiliaries used according to this invention contain in the molecule at least two lactam radicals, that, moreover, outside the lactam radical there is in each molecule at least one hetero atom and each lactam radical has at least two additional carbon atoms in the connecting chain. There may also be present in the connecting chain more additional carbon atoms or two or more additional hetero atoms per lactam radical may be present in the connecting chain. Besides the lactam compounds described in detail above, there may also often be used with special advantage the products further modified by adding low molecular weight organic radicals. For example, by alkylating the lactam compounds containing nitrogen as the hetero atom in the connecting chain, there can be obtained products with changed retardation action and those with specially favorable levelling properties. The alkylation may be with aliphatic radicals which contain not more than 5 carbon atoms. For the alkylation there are suitable, for example, halogen-paraffins, such as methyl, ethyl or propyl chloride, alkylene oxides, especially ethylene and propylene oxide, or acrylonitrile. If the nitrile groups contained on the nitrogen atom in such lactam compounds are hydrogenated to the corresponding gamma-amino compounds, highly active products are also obtained. Especially active lactam compounds are also obtained by reacting lactam compounds which contain in the connecting chain with dihalogen parafiins, as for example ethylene chloride, dichlordimethyl or dichlordiethyl ether. In this way there are obtained lactam compounds which contain at least four lactam radicals in the molecule.

Products which contain more than two lactam radicals in the molecule are also obtainable in the following way:

To a polyalkylene polyamine there are added as many cyanoethyl groups (ethyl-nitrile groups) as there are hydrogen atoms attached to the nitrogen atoms. The resultant nitrile derivatives are catalytically hydrogenated under known conditions to form the corresponding polyamines which are then reacted with lactones. Thus, for

example, from diethylene triamine there is formed the compound:

L-CHz-CHrCH GH -CHu-CHa-L N-CHa- CHr-N-CHr C HrN L -CHg-CHn-OH: H, CHrCHz-CIIz-L lHg 31H; i.

in which the radicals L represent identical or different of the said lactam radicals.

The dyeing auxiliaries according to this invention have an excellent levelling action in dyeing and on dyeings, for example with vat dyestuffs and sulfur dyestuffs. On the contrary, the agents have no pronounced surfaceactive properties; they do not froth and wet in the concentrations necessary for levelling. They have a basic reaction when they contain nitrogen atoms in the connecting chain. It is possible to dye in the presence of the said dyeing auxiliaries, but they may also be used for a levelling aftertreatrnent of unequal dyeings. The auxiliaries may be used in amounts of 0.1 to 20 grams per litre, preferably 0.25 to 1 gram per litre.

When dyeing in apparatus (by which we mean the apparatus for dyeing cheeses, warp beams, cakes and the like) the subject dyeing auxiliaries, are preferably added after the vatting of the dyestuff. When working according to the pigment padding jigger development method, the auxiliary is added to the development bath. The new dyeing auxiliaries are suitable for all hitherto known dyeing methods in which vat and sulfur dyestuffs are used for dyeing.

It is true that pyrrolidone itself and substitution prodnets of pyrrolidone-which, however, have always contained only one pyrrolidone radical in the moleculehave been used as dyeing auxiliaries, especially as leveling agents. It could not have been foreseen, however, that the lactam derivatives used according to this invention would have many times the yield as compared with the most efficient dyeing auxiliary containing a single pyrrolidone radical in the molecule. On the other hand, it is very remarkable that the lactam derivatives used according to this invention exert on the dyestuff no retarding action or a retarding action which is conspicuously less as compared with the leveling agent with affinity for the dyestufi hitherto usual. It has also been stated that the reaction product of butyrolactone and diethylene triamine, acylated with aliphtaic radicals, which contain at least six carbon atoms, exhibits wetting, foaming and cleansing power and can therefore be used as a textile auxiliary, for example in dyeing and leveling. The excellent properties of the substances used according to the present invention could not be deduced from this fact however, for the leveling action of the said known compounds is very small as compared with that of the compounds according to this invention.

The superiority of the lactam compounds now proptmed can be clearly shown by comparative tests. For example, when two identical samples of cotton which have been dyed with a vat dyestuff are treated under otherwise identical conditions together with undyed cotton in separate dyeing baths without dyestuff (blank vat) for 45 minutes at C., one bath (a) containing an auxiliary according to the present invention (reaction product of 2 mols of butyrolactone and 1 mol of diethylene triarnine) and the other bath (b) containing an agent (the reaction product according to (a) reacted with lauric acid chloride), the following is observed: the undyed cotton in bath (a) is dyed powerfully and the color strength of the cotton dyed from the start is correspondingly lessened (dye equalization). This good effect is shown, for example, at 0.25, 0.5, 1 and 5 grams of auxiliary per litre of liquid. Corresponding to the increasing amount of auxiliary, the dye equalization from the dyed to the initially undyed cotton becomes more intense. The cotton skeins treated in bath (b) present on the other hand quite a different picture: with small amounts of the added agent, the dye equalization from the dyed to the undyed cotton is less than with the same amount of the auxiliary used in bath (a). If the amount of the agent in bath (b) is increased, for example to 0.5, 1 and 5 grams of agent per litre of liquid, the dye equalization does not become more intense, but becomes worse. The cause of this is that the agent in bath (b) strips the dyestuff from the dyed cotton but does not allow it to be absorbed, or absorbed to the same extent, by the initially undyed cotton. The dye equalizing action of the agent used in bath (b) is thus small (small leveling action) and, moreover, this agent also retains the dyestuff in the bath (strong retarding action). The agent used in bath (b), and similar agents, therefore, cannot be regarded as useful levelling agents.

The production of the addition products of butyrolactone to polyalkylene polyamincs is possible according to the following directions, the parts specified being parts by weight:

I. (a) 206 parts of diethylene triamine (2 mols) are gradually mixed while stirring with 387 parts of butyrolactone (4.5 mols). Marked heating thereby occurs. The mixture is kept for 4 hours at 230 C. and for another 2 hours at 250 C. In this way, and then under a vacuum of 5 mm, constituents volatile up to 130 C. are distilled off. 453 parts of the desired dilactam are obtained as a viscous brownish colored water-soluble liquid.

(b) By reacting this compound obtained according to 1(a) with 1 mol of acrylonitrile in the usual way there is obtained a water-soluble viscous liquid which constitutes the derivative substituted on the original secondary amino group by the beta-cyanoethyl group:

CH: CN

in which In--0lh 14:11:53 (E0 N l (0) By hydrogenating under known conditions the derivative obtained under 1(1)), there is obtained the corresponding compound substituted on the nitrogen atom by the gamma-aminopropyl group, which is clearly soluble, basic reacting, viscous oil:

LOII:CH:-NCH2CH2L Hr-CI'I:-CH2-NH3 (d) By adding 1 mol of ethylene oxide to the dipyrrolidone compound accessible according to 1(a), there is also obtained a clearly water-soluble compound in which the nitrogen atom is substituted by the beta-ethoxy group:

LCHz-CH,NCH CH L H2CH2-OH II. (a) 262 parts of dipropylene triamine (2 mols) are mixed with 380 parts (4 mols+10% excess) of butyrolactone while stirring. The temperature is brought to 200 to 230 C., kept for 3 hours at 230 C. and finally raised to 250 C. for 2 hours. After distilling off volatile constituents in vacuo at 5 mm. up to 155 C., there remain 517 parts of a water-soluble, brownish colored, viscous liquid of strong basic reaction:

L-CIII-CH2CEI)l}r OlI2CI[3' CIIE"-L H (b) By using-in the procedure of Example II(a)- 290 parts of N-methyl-dipropylene triamine (2 mols) or 318 parts of N-ethyl-dipropylene itriamine (2 mols) instead of 262 parts of dipropylene tn'amine under otherwise identical conditions, there are also obtained clearly water-soluble, viscous, brownish colored liquids which are the corresponding N-alkyl derivatives:

-N- or I\I- H, OHPCH] III. 380 parts of butyrolactone (4 mols+10% excess) are mixed with 292 parts of triethylene tetramine and heated while stirring to 230 C., kept for 3 hours at this temperature and finally heated for another 2 hours at 250 C. After distilling off volatile constituents, finally in a vacuum of 5 mm. up to 130 C., there are obtained 557 parts of the product clearly soluble in water:

IV. By using 440 parts of valerolactone (4 mols+10% excess) or 496 parts of gamma-ethylbutyrolactone instead of 380 parts of butyrolactone in Examples 1(a), II(a), lI(b) and III and working under otherwise identical conditions, there are also obtained clearly watersoluble resinous products which are the corresponding dipiperidone compounds or the compounds substituted by ethyl on the pyrrolidone ring. These have the formulae given above but with L equal to N N l V. (a) 264 parts of di-(gamma-aminopropyl)ether (2 mols) are heated to 70 C. and while stirring there are added 380 parts of butyrolactone (4.4 mols). After the heating up has ceased, the whole is heated first for 2 hours at C. and then for another 4 hours at 240 C., whereby the water of reaction is distilled ofi. In a vacuum of 5 mm. Hg there is then distilled off the excess of butyrolactone and the remaining water of reaction completely within 1 hour. 520 parts of a brownish highly viscous residue are obtained which is clearly water-soluble and reacts neutral:

(b) By heating 263 parts of 1.2.3-tri-(gamma-aminopropoxy)-propane (1 mol) and 290 parts of butyrolac tone (3.3 mols) under the same conditions as described under V(a), there is obtained as a residue 450 parts of crude 1.2.3 tri (gamma-pyrrolidyl propoxy)-propane which is clearly water-soluble highly viscous oil:

VI. 240 parts of sodium sulfide containing water of crystallizaiton (Na S.9H O) (1 mol), dissolved in 400 parts of ethanol are heated to boiling. 295 parts of N-beta-chlor-ethylpyrrolidone (2 mols) are added dropwise dissolved in 200 parts of ethanol and the whole heated for 3 hours under reflux. The solvent is then evaporated. 380 parts of a clearly soluble residue are obtained which besides sodium chloride contains the sulfur-containing dipyrrolidone derivative.

VII. Into l3l parts of diethylene triamine (1 mol) there are slowly dripped at 60 C. 424 parts of acrylonitrile (8 mols) in the presence of a polymerization inhibitor and the reaction mixture is then kept at this temperature for 7 hours. The excess of acrylonitrile is removed by distillation in vacuo at 12 mm. Hg up to 50 C. The residue obtained (454 parts) is hydrogenated in 1000 parts of methanol saturated with ammonia in the presence of 70 parts of moist Raney cobalt at 100 C. and 200 excess atmospheres of hydrogen until the calculated amount of hydrogen (10 mols) has been absorbed. The catalyst is filtered off, the solvent evaporated in vacuo and the residue (460 parts), which is penta-aminopropyl-dipropylene triamine, is reacted under the conditions described under V(a) with 475 parts of butyrolactonc (5.5 mols). A dark tough resin is obtained which is readily and clearly water-soluble.

The following examples will further illustrate this invention but the invention is not restricted to these examples. The parts specified in the examples are parts by weight.

Example 1 Mereerized cotton yarn which has previously been dyed with 2 percent of the dyestufi of the constitution:

is treated, together with the same amount of undyed yarn, for hour in a blank vat at 60 C. in the goods to liquor ratio of 1:20 with the addition of 0.25 gram per liter of the reaction product of 1 mol of triethylene tetramine and 2 mols of butyrolactone. After only a few minutes, the dyestuff visibly begins to migrate to the undyed material. At the end of the experiment, the white material is powerfully dyed, whereas in a comparative test without the addition of the auxiliary it remains almost unchanged under the otherwise identical conditions.

By replacing the said leveling agent by the compounds obtainable according to 1(a) to (d) or II(a) or II(b), a similar effect is observed. The differences in the action of the individual products are not very great and moreover depend on the dyestufi.

Example 2 The superior action of the agents used according to this invention may be seen from the following comparative tests.

A blank vat is prepared which contains in each liter 5 grams of sodium dithionite and 12 cc. of caustic soda of 38 Baum strength. Into this vat:

(a) Without further addition;

(I) With the addition of 5 grams per liter of N-methylpyrrolidone;

(0) With the addition of 1 gram per liter of the condensation product of 1 mol of diethylene triamine and 2 mols of butyrolacetone;

(d) With the addition of 5 grams of the agent specified under (c);

there are treated together for 45 minutes at 60 C. in the goods to liquor ratio of 1:30, an undyed cotton skein and a cotton skein which has been dyed with 2 percent of the dyestufi specified in Example 1 by the usual IN method. During this treatment, an equalization of dyestuif between the dyed and undyed cotton skeins takes place. The extent of the equalization, i.e. the uniformity of the shade of color after the treatment of the cotton skeins, is a measure of the action of the leveling agent used.

Comparison of the cotton skeins which after treatment in the blank vat, are rinsed, oxidized and finished oil in the normal way, shows that in sample (c) the same leveling action has occurred as with sample (b), although in the case of sample (b) five times the amount of a known agent have been used. The sample (d), in which the same amount of leveling agent has been used as in sample (b), shows the maximum action of the products used according to this invention.

Example 3 Staple fiber yarn is dyed on a mechanical yarn dyeing machine (according to Gerber) according to the IN method in a goods to liquor ratio of 1:30 with 2 percent of Indanthren Brilliant Green B (powder, fine, highly concentrated, for dyeing) (C.I. 59825/1956), the dyebath receiving an addition of 1 gram per liter of the product obtainable according to IV from 2 moles of gammaethyl-butyrolactone and l rnol of triethylene tetramine.

The dyestutf goes on to the fiber slowly and uniformly. The dyestulf is free from froth and the yarn does not float. The final liquor contains relatively little dyestuff. After the usual finishing off, the yarns are dyed in a level manner and well through. When dyeing is effected without the addition of the dyeing auxiliary, the dyestutf goes on so quickly that the dyeing is not level. If a surface-active leveling agent of the type of a hydroxyethylated fatty alcohol or fatty amine or quaternary surface-active ammonium compounds are used it is true that level dyeings are also obtained but too much dyestuff remains in the residual liquor and the dyebath foams, so that the yarns begin to float on the bath. The mechanical manipulation is thereby hindered and the dyeing made impossible.

Instead of the above-mentioned, well suited leveling agent, also suitable are the dior tripyrrolidone compounds obtainable according to V(a) and (b) which have oxygen atoms as hetero atoms between the lactam rings. They differ from the first-mentioned agents in that their retarding action is even less.

Example 4 Cheeses spools or warp beams of cotton are dyed in a closed dyeing apparatus (according to Obermeier) according to the IN method in the goods to liquor ratio of 1:10 with 1 percent of Indanthren Blue BC Powder, fine ,for dyeing (Cl. 69825/1956). With an otherwise identical method of operation, 1.5 grams per liter of the product prepared according to II(a) are added to the dyebath as the sole leveling agent. After finishing off as usual, the dyed wound bodies are dyed through with good equality, clear shade and unobjectionable uniformity. Only a little dyestulr' remains in the dyebath.

In the same way as the product prepared according to 11(a), there are also suitable as leveling agents the reaction products of the same with ethylene chloride, with dichlordimethyl ether, with dichlordiethyl ether and the pentapyrrolidone compound obtainable according to VII. With these products the retarding action is less than with the first-mentioned products.

Example 5 Cotton waterproof popline is dyed on the automatic jigger, and indeed the fabric previously padded on the foulard with 1 percent of Indanthren Olive T (powder, fine, for dyeing) (C.I. 69525/1956) is developed in the goods to liquor ratio 1:5 on the jigger by the IN method. The development bath, apart from the usual additions of hydrosulfite, caustic soda solution and padding liquor, receives no addition of auxiliaries other than 2 grams per liter of the product prepared according to I (a). With a slight retardation action there is obtained a level, well through-dyed and remarkably solid toning.

If the product prepared according to 1(a) and reacted with ethylene chloride or dichlordiethyl ether is used, excellent effects are also achieved.

Example 6 A cotton yarn dyed with 2 percent of Indanthren Blue- Green FFB (powder, fine, for dyeing) (Cl. 70305/ 1956) is treated together with the same amount of undyed yarn of the same kind in a blank dyebath according to the IN method in the goods to liquor ratio 1:30 for hour. The object is that after treatment the two yarns should have the same shade of color and the same depth of color (equalization).

If no auxiliary is added to the blank dyebath, the equalization is very slight. When known leveling agents are added, for example, 2 grams per liter of hydroxyethylated octadecyl alcohol (mol ratio 20:1), the equalization is relatively good but the color depth of the dyeings is small and the loss of dyestuffs in the bath is large.

When 0.5 gram per liter of hydroxyethyleated octadecylamine (mol ratio 7:1) which has subsequently been peralkylated with dirnethyl sulfate is added, there is also a certain equalization present but the shade of color is displaced towards blue and indeed strongest on the yarn which originally was white, and, moreover, the loss of dyestuif in the dyebath by reason of the retarding action of the auxiliary is great.

When 5 grams per liter of rnethylpyrrolidone or caprolactarn or the reaction product of pyridine with chloracetic acid, a clearly better equalization can be observed than without addition.

The same good result can be achieved with only 1 gram per liter of the product specified in Example 1 or Example 3. If 5 grams per liter of these products are used, there is obtained a practically complete equalization, there is no change in shade of color and the dyestutf loss by retardation is relatively small.

Example 7 5 to grams per liter of the reaction product of symmetrical dichlordiethyl thioether with pyrrolidone, which is also obtainable in the manner described in VI, are added in the continuous dyeing of cotton piece goods with vat dyestuffs by the pad-steam method. A considerably more level and better dyed-through goods are obtained with a high dyestufi yield, than without the said addition.

Example 8 Staple fiber yarn is dyed in the vat with percent Immedial Indoviolet B extra (CI. 53440) in a goods to liquor ratio of 1:30 at 95 C. with 8 percent of soda, 60 percent of sodium sulfide, 50 percent of Glaubers salt for 1 /2 hours. The dyeing tends to bronze, is not fast to rubbing and is unequal. A dyeing free from objection is achieved by the addition of 0.5 to 1 gram per liter of the product prepared according to 1(a).

Example 9 Cotton tricot is dyed on the reel vat with 0.22 percent of lndanthren Blue 3 GN powder ((3.1. 69840/ 1956) by the normal dyeing method. The dyeing is unequal. If, however, 0.5 gram per liter of the piperidone compound from 2 mols of valerolactone and 1 mol of diethylene triamine according to IV or a pyrrolidone compound substituted at the hetero atom by an alkyl group according to II(b) be added to the dyebath, the dyeing is considerably more solid and is unobjectionably level by an otherwise identical manner of operation.

We claim:

1. In the process of dyeing textile materials selected from the group consisting of cellulose and staple fiber yarn of regenerated cellulose with vat dyestufis and sulfur dyestuffs the step which comprises levelling the dyeings in an alkaline bath with a compound of the following general formula to 7 ring members, the said lactarn groups being attached by their nitrogen atoms to R and R wherein R and R 10 represent carbon chains with from 2 to 6 carbon atoms in each chain, R represents a carbon chain with from 1 to 6 carbon atoms in the chain, X represents a member of the class consisting of oxygen, sulfur,

N-CHg-CHrCHrN D dyeing process.

4. A process as in claim 1 wherein the levelling agent has the formula IIgC-CO COCII2 /NC HrCHr-NII-C HrOIIrNH- OHn-C Hr-N HaC-Clh CH -OH:

5. A process as in claim 1 wherein the levelling agent has the formula HnC-CO CO-CH! N-CHz-CIIz-N-CHrCHrNCHrCHr-N H: CH: H: Ha IEC- H H1 H 5N N 6. A process as in claim 1 wherein the levelling agent has the formula 7. A process as in claim 1 wherein the levelling agent has the formula 8. A process as in claim 1 wherein the levelling agent has the formula 9. A process as in claim 1 wherein the levelling agent has the formula 10. In the process of dyeing textile materials selected from the group consisting of cellulose and staple fiber yarn of regenerated cellulose with vat dyestuffs and sulfur dyestuffs the step which comprises levelling the dyeings in an alkaline bath with a compound which contains at least two lactam groups with from 5 to 7 ring members in the molecule, the said compound containing between any two lactam groups a connecting chain which has either end linked to the nitrogen atom of the lactam groups, which connecting chain includes at least one heteroatom selected from the group consisting of oxygen, sulfur, and nitrogen, the said lactam groups and the said heteroatoms being connected by a. carbon chain containing from 2 to 6 carbon atoms, and the said heteroatoms being connected to each other by carbon chains containing from 1 to 6 carbon atoms.

11. The levelling process according to claim 10 wherein the levelling agent has from 3 to 5 lactam groups.

References Cited in the file of this patent UNITED STATES PATENTS Lubs Dec. 17, 1940 Haynn May 12, 1942 Lucas June 5, 1951 Puetzer Dec. 25, 1956 Mautner Oct. 4, 1960 FOREIGN PATENTS Belgium May 17, 1954 OTHER REFERENCES Hansen: Amer. Dyest. Rep, February 1, 1954, p. 72. Holmes: Amer. Dyest. Rep., September 26, 1955, p. 704. 

1. IN THE PROCESS OF DYEING TEXTILE MATERIALS SELECTED FROM THE GROUP CONSISTING OF CELLULOSE AND STAPLE FIBER YARN OF REGENERATED CELLULOSE AND STAPLE FIBER SULFUR DYESTUFFS THE STEP WHICH COMPRISES LEVELLING THE DYEINGS IN AN ALKALINE BATH WITH A COMPOUND OF THE FOLLOWING GENERAL FORMULA 